1. Field of the Invention
The invention relates to a method and an apparatus for regulating outflow, particularly from rain water tanks.
2. Prior Art
Rain water tanks are used to intermediately store the rain falling in the case of very sudden rainfall in such a way that watercourses are not endangered. It is virtually impossible to forecast heavy rain and large quantities of water are involved.
It has hitherto been conventional practice to restrict or constrict the outflow from rain water tanks, i.e. to provide devices which, in the case of a large opening, have a high flow resistance. For this purpose, inter alia, waste water restrictors with turbulence or vortex chambers are used, which operate without moving parts. They have large cross-sections, which are not very susceptible to blockages.
An example of such a waste water restrictor is known from German patent No. 26 43 029 and produces an outflow which increases roughly proportionally to the square root of the water level.